DE 100 42 475 A1 discloses a drive train arrangement for a low-floor bus, which bus possesses a rear-mounted driving motor, which is oriented transversely to the direction of travel. This driving motor inputs driving energy to the rear axle by way of an angular bevel gear connection. The rear axle in this connection is generally referred to hereinafter as the “portal axle”, which axle has structural characteristics convenient for low-floor bus construction. An angular bevel gear drive unit is employed, which consists essentially of a housed gear combination with a motor sided, input driver bevel gear and a corresponding output bevel gear. The latter is bound to the rear axle by a complementary crown gear attachment. The input drive, motor sided bevel gear is co-axial with the motor shaft, which shaft lies transverse to the direction of travel and engages with the output drive bevel gear, which is placed on an intermediate shaft leading to the rear axle. The meshing engagement of both bevel gears, as seen in the direction of travel, is placed ahead of the transversely situated motor axis, i.e., located between the motor drive shaft and the above portal axle. By way of this positioning, a short intermediate shaft is allowable and hence a space-saving construction is thereby achieved.
A problem then arises, if such a drive arrangement is to be designed for both right- and left-handed driving, respectfully as is found in the United States and England where a door may be located between the portal axle and the motor, which is placed transverse and off-center in the rear. This door may be located on the right side of the bus in a case of left-hand drive construction or, conversely, may be located on the left side, in case of right-hand drive construction. Since the widest possible door opening to the rear must be assured, then the placement of a crown gear for rear axle drive is necessary on an off-center wheel-side. Since the motor for right-hand drive travel must be rotated 180° about its vertical axis and counter to that required for left-hand drive, the same direction of rotation must be retained for this reason; a reversal of the direction of rotation for the rear axle of the bus becomes necessary. It is known that for this purpose, an additional spur gear is installed behind the bevel gear stage, which obviously presents the disadvantage of an increase in constructional height, as well as higher costs and a lowered degree of efficiency.
It is the purpose of the present invention to create a drive arrangement of the type described in the introduction, which brings about a change of rotational direction upon a change of position of the driving motor and to do so without an additional demand for space and without a diminution of efficiency.